Abstract: The disclosure relates to a ram extruder including an extruder barrel having an extrusion die at one end and a hydraulic ram at the other end having a piston which is advanced along the barrel by the ram to displace material in the barrel through the extrusion die. To facilitate loading of the barrel a loading port is provided in the side of the barrel adjacent said other end of the barrel through which the barrel may be charged after retraction of the piston following an extrusion operation and a port closure device is provided to close the port after extrusion and evacuate air from the barrel prior to advancing the piston past the port to minimize the air contained in the barrel prior to the extrusion operation.

Abstract: The disclosure relates to an apparatus for applying a polymeric covering to a workpiece such as a cylindrical workpiece (10). In order to apply smooth surfaced coating firmly bonded to the workpiece in a single operation the workpiece is rotated in a lathe about an axis (11) and a rubber applying head is traversed parallel to the axis along the workpiece. The head has a freely rotatable tapered feed roller (19) forming a nip with the workpiece to apply polymeric material to the workpiece, a main roller (23) adjacent the feed roller and also forming a nip with the workpiece to pressurise and render plastic the rubber coating applied by the feed roller to masticate and compound the layer, a pressure surface (24) adjacent the main roller and incorporating a retractable plough (25) to dig into the rubber coating and release any entrapped air and a finish roller (26) to apply the required surface finish to the rubber coating.